title: Metabolic engineering of Escherichia coli for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose.
abstract: The Escherichia coli XL1-blue strain was metabolically engineered to synthesize poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] through 2-ketobutyrate, which is generated via citramalate pathway, as a precursor for propionyl-CoA. Two different metabolic pathways were examined for the synthesis of propionyl-CoA from 2-ketobutyrate. The first pathway is composed of the Dickeya dadantii 3937 2-ketobutyrate oxidase or the E. coli pyruvate oxidase mutant (PoxB L253F V380A) for the conversion of 2-ketobutyrate into propionate and the Ralstonia eutropha propionyl-CoA synthetase (PrpE) or the E. coli acetyl-CoA:acetoacetyl-CoA transferase for further conversion of propionate into propionyl-CoA. The second pathway employs pyruvate formate lyase encoded by the E. coli tdcE gene or the Clostridium difficile pflB gene for the direct conversion of 2-ketobutyrate into propionyl-CoA. As the direct conversion of 2-ketobutyrate into propionyl-CoA could not support the efficient production of P(3HB-co-3HV) from glucose, the first metabolic pathway was further examined. When the recombinant E. coli XL1-blue strain equipped with citramalate pathway expressing the E. coli poxB L253F V380A gene and R. eutropha prpE gene together with the R. eutropha PHA biosynthesis genes was cultured in a chemically defined medium containing 20 g/L of glucose as a sole carbon source, P(3HB-co-2.3 mol% 3HV) was produced up to the polymer content of 61.7 wt.%. Moreover, the 3HV monomer fraction in P(3HB-co-3HV) could be increased up to 5.5 mol% by additional deletion of the prpC and scpC genes, which are responsible for the metabolism of propionyl-CoA in host strains.
authors.affiliation: Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Yang
authors.forename: Yong Jun
authors.initials: YJ
authors.lastname: Choi
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Kyoung-Hee
authors.initials: KH
authors.lastname: Kang
authors.forename: Hyuk
authors.initials: H
authors.lastname: Lee
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Oh
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Lee
authors.forename: Si Jae
authors.initials: SJ
authors.lastname: Park
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
mesh_terms: D016360:Clostridioides difficile / Q000201:enzymology / Q000235:genetics; D020118:Cupriavidus necator / Q000201:enzymology / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D011091:Polyesters / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D005947:Glucose; D011091:Polyesters; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates